Signal Analysis of Irradiation,Temperature and Primary Production in a Small Artificial Pond. II. The Residual Spectra

Irradiation, water temperature and dissolved oxygen of a small artificial pond were continuously recorded over a two year period. Following the elimination of previously estimated mean trends and forced annual patterns (LINGEMAN 1980) a spectral analysis procedure is proposed and executed for the residual signals of total diurnal irradiation, diel mean temperature and diurnal gross primary production. The residual power spectrum of diurnal irradiation was shown to be essentially the one of a white noise. Several higher frequencies were significantly present in both the signals of temperature and production. Some consideration is given to the cross correlation between the latter two parameters.